Carrier aggregation (CA) is a method used by telecommunication devices to increase bandwidth, for example in 4G LTE (Long-Term Evolution) devices. CA comprises aggregation of two or more component carriers (CC), with one example allowing up to five CCs. By aggregating a plurality of CCs, greater overall bandwidth may be realized. For example, with five CCs at 20 MHz each, an overall bandwidth of approximately 100 MHz is possible. For a telecommunications service provider that does not own a full 100 MHz of contiguous bandwidth, this may enable an overall 100 MHz bandwidth. Three example modes may be provided. These include contiguous, non-contiguous, and intra-band aggregation.
CA does not affect the full protocol stack, however. Rather, one CC may be designated as a primary, and the additional CCs may then be treated as extra transmission resources. Therefore, CA signaling is transparent, for example, to Packet Data Convergence Protocol (PDCP and Radio Link Control (RLC)) layers. The Medium Access Control (MAC) layer may provide logic to multiplex a plurality of CCs.